How explosives, robots and snowmobiles come into contact with apocalyptic glaciers

But the news from Icefin was not so good. The water is warm enough to melt glaciers swirling around the Thwaites’ landline — the exact point where the ice meets the land — and the line has receded more than a mile since 2011. That means there’s more to it now. More seawater is in contact with the bottom of the glacier, which means more melting. The ice “is the most turbulent of these,” says Washam, “it has really interesting undulating, undulating features close to the ground line.” These features are hot spots of melting.

If the underside of the Thwaites were flat, fresh water melting from the ice would collect underneath it like a lid, keeping it from being further melted by warmer ocean water. “It’s basically going to counteract the movement of ocean heat into the ice,” Washam said. Instead, the undulating, steep features break the cap of the fresh water, allowing warmer water to come into contact with the ice.

This revelation gives glaciologists insight into how glaciers everywhere may be in decline — and is a factor they haven’t taken into account in modeling. “This other type of melting pattern along these steep ice surfaces is not present in the iceberg models,” said Washam. “This shows us this is something that needs to be considered if we are to more accurately project Antarctica’s contribution to sea-level rise.”

Lizzy Clyne, geophysicist and glaciologist at Lewis and Clark College, and another conference presenter, discovered additional trouble at the landing zone — using explosives, astronauts The crew descended into a hole 20 feet deep in the ice. (“It was like a firework,” says Clyne. “It would hurt you if it exploded in your hand, but it didn’t look like a giant bomb.”) An array of seismometers on the measuring surface measure the energy of the explosion. return what’s underneath the ice. Using that data, Clyne can tell if it’s water or solid soil. It works like Pettit’s ground-penetrating radar, and indeed Clyne also combines seismic data with radar data.

Data Clyne collected from 2018 shows that because the Thwaites ice shelf is floating in the sea, it tilts during high and low tide. As it rises, warmer water slides over the ground and beneath the ground ice, causing it to still melt more. That is another important dynamic that is not shown in the model of melting ice. “It’s the kind of action where you can pull frozen seawater a few degrees inland a little further than we initially thought,” Clyne said. “It can be like a layer of water a few centimeters thick, a thin layer going further inland. But that’s all it takes to thaw.”

Now, scientists are putting these trends together — cracks in the ice shelf, the complexity of the glacier’s underside, and tidal pumping — they’ve landed on a stark assessment of the River Delta. The Apocalypse: It is decomposing in more ways than they previously understood. If it melted completely and swept away the surrounding glaciers, sea levels would rise by a total of 10 feet. “In my view,” Clyne said, “if we are going to have a very rapid sea level rise over the next few decades, that is unlikely to happen unless the Thwaites are contributing a lot to it.”

By pulling radar on sleds, manipulating torpedo-launching robots, and placing explosives, scientists are building an increasingly clearer picture of the most important glacier on Earth. “I personally do not have the ability to control sea level rise and I cannot fix global warming on my own,” says Clyne. “But what we can do is study and understand what’s going on, what’s going to happen and how to reduce it as much as possible.”

Stories with WIRED are more amazing